Ronaldo has not played since limping out of Madrid’s quarterfinal first leg against Borussia Dortmund on April 2, missing his team’s last four games [including last week’s 2-1 Copa del Rey final win over Barcelona] with a mixture of knee and thigh problems.

The Portugal captain has trained for two days with his teammates, but might not yet be ready to start such a huge game, the Blancos coach told his official pre-game news conference.

Cristiano Ronaldo may return against Bayern Munich.

“Cristiano trained normally today, he has trained well these last days,” Ancelotti said. “Tomorrow we will have another test to be sure. He wants to play and we are confident, but the decision will be made tomorrow. If there is a risk he will not play.”

Ancelotti would not comment on reported differences of opinion between Madrid’s medical team and the player’s camp, but did stress that he did not want to risk any further setback which could rule Ronaldo out of next week’s second leg in Munich.

“Cristiano has been injured and undergone treatment,” Ancelotti added. “He has consulted with the club’s doctors, has done his recovery work, and has been training for three days, two last days with the group normally. He feels good, we feel good, tomorrow we will do a physical test and if he feels good he will play.

“The tie will not be decided [in the first leg], maybe we will get an advantage, but it will be decided next Tuesday. We must also think whether Cristiano on the bench could give us more options. Any minute could be the decisive minute.”

Last week’s Copa del Rey final match-winner Gareth Bale missed training on Monday with flu, but was back taking a full part on Tuesday morning.

“[Bale] had a small problem yesterday, but today he is fine,” Ancelotti said. “The goal he scored against Barcelona, in a final, it is normal that it will give him more confidence. He had some problems at the start, but not anymore. He has scored a lot of goals, and played for the team. He is going to improve even more next season as he is training with us and has the good luck of not playing the World Cup.”

Although Brazilian left-back Marcelo is back fit after a month out with a hamstring injury, Ancelotti confirmed that Fabio Coentrao would keep his place in the XI. Sergio Ramos is expected to play in central defence despite a niggling neck-muscle injury, while Isco is most likely to drop out should Ronaldo start.

Ancelotti said he expected the Bayern game to take a similar pattern to that Copa final, given current Munich coach Pep Guardiola’s Camp Nou past.

“We played against Barcelona with 11 players, very solid and helping each other,” the Italian said. “Tomorrow will be the same. We will need a lot of good defensive work, and to control the play to show our own quality. The philosophy that Guardiola has put in is more or less the same [as at Barca], obviously with different players but also of good quality. But I do not believe the coaches will decide this semifinal, the players will do that.”

Asked towards the end of the session for his thoughts on David Moyes being sacked as Manchester United manager on Tuesday morning, Ancelotti -- tipped as a potential successor at Old Trafford -- said he had been surprised to hear the news, not because of Moyes’ performance, but because of United’s history.

“I have sympathy for David Moyes,” Ancelotti said. “In general this is the coach’s life, when things do not go well you have to leave. It is normal, Moyes will have another team, another opportunity. I was surprised a little as Man United do not usually do this, in another club it might be normal, but after 24 years of Sir Alex [Ferguson], it is a bit surprising.”